Multilayer ceramic capacitors are manufactured by alternately laminating ceramic dielectric layers and internal electrode layers, and then firmly pressing and sintering them to form an integrated body. Barium titanate powder slurry is widely used for the ceramic dielectric layers. Recently, the ceramic dielectric layer is particularly made to be thinner, so as to meet requirements of compact design and increased capacity. In order to obtain a ceramic dielectric layer having satisfactory voltage tolerance characteristics, the particle size distribution of the barium titanate powder must be in a narrow range of 0.2 to 1.0 .mu.m, and the dispersion characteristics in the slurrying of the barium titanate powder must be superior. If the dispersion characteristics of the barium titanate powder in the slurry are not good, the barium titanate particles partly agglomerate after sintering, so that the density distribution of layer is not uniform. As a result, an insulated barium titanate layer is formed in some cases, and this therefore poses a problem in that the capacity of the condenser may not be sufficient.
Heretofore, barium titanate powders have been produced by mixing titanium compounds and barium compounds, and then sintering them so as to cause a solid phase reaction. However, in such a production method, the above chemical compounds are made to react at high temperatures, causing the particle sizes of the obtained barium titanate powders to increase, the particle size distribution thereof to broaden, and the shapes thereof to become irregular. Therefore, the dispersion characteristics of the barium titanate powder in the slurry is not so good. Japanese Unexamined Patent Publication No. 330824/93 discloses a production process in which a cubic spherical barium titanate powder having good dispersion characteristics can be obtained. According to the disclosure, hydrogen peroxide is added to a titanium compound and a barium compound so as to wet react them and obtain a barium titanate powder. Furthermore, the barium titanate powder having particle sizes ranging from 0.2 to 5 .mu.m, obtained by this production process, is presintered at temperatures ranging from 600 to 1100.degree. C. Japanese Unexamined Patent Publication No. 155532/85 discloses a production process for a barium titanate powder by a wet method. According to the disclosure, the hydrolysis products of a titanium compound, a water-soluble barium salt, and a water-soluble strontium salt are reacted in a strong alkali, to obtain fine particles of barium titanate strontium.
In addition, Kyng-Hee Lee disclosed a wet synthetic method in the J. Korean Ceram. Soc., vol. 21, no. 4 (1984) pages 323-326. According to this synthetic method, a mixed solution of titanium chloride and barium chloride is reacted with KOH at 100.degree. C. or less, so that a finely crystalline barium titanate powder of high purity is efficiently obtained. The wet synthetic method has advantages in that the control of particle size is easy, fine globular barium titanate powders can be obtained, and by-products other than barium titanate are not included in the fmal product.
For a barium titanate powder used for a ceramic dielectric layer of a multilayer ceramic capacitor, the dispersion characteristics in the slurry condition is the most important, as mentioned above. In the production processes disclosed in the above references, although improvements are made in the particle size, the particle size distribution, and the shape of the barium titanate powder, the dispersion characteristics of the barium titanate powder are still not satisfactory. Therefore, the agglomeration occurs when it is actually slurried, and satisfactory characteristics for dielectric layers have not yet been obtained.